MVHR wall mount - vibration

[hauntedicecreamvan]

I am fitting MVHR to a bungalow. Originally it was going into a kitchen wall cabinet (it's a Zehnder Comfoair 180) but duct runs are much nicer if I install it in the former airing cupboard. The airing cupboard is 600x600 and blockwork on all three sides. These walls back onto the bedrooms.

 

Due to the location of a ceiling joist, the MVHR unit needs to sit forward from the back wall roughly 150mm. This allows the ducts to pass straight up without additional 45 degree turns.

 

Given the proximity to bedrooms, and the 150mm of dead space behind the unit, I was wondering if it is worthwhile building some isolation in between the blockwork and unit?

 

I was going to build a timber frame fixed directly to the back and side walls, filled with Rockwool RWA45, and faced with 18mm plywood. But that doesn't do anything to physically isolate the unit from the wall, only added mass, and does this risk making the frame become a mini stud wall that resonates more than the blockwork would?

 

Is it worthwhile going through the effort of building a "floating" timber frame to mount the MVHR unit on, with spring/rubber mounts to keep it in place?

 

Any advice or tips welcome.

Edited 5 hours ago by hauntedicecreamvan

[JohnMo]

I have an MVHR in a hall cupboard, but with a bedroom either side. My walls are wooden stud walls.  The mounting face for the MVHR, has a double layer of 18mm ply. The stud walls are filled with Rockwool Flexi and 12.5mm plasterboard elsewhere. No vibration and zero noise. I did not use anti vibration mounts.

[hauntedicecreamvan]

Thank you, sounds like I might be overthinking this. I should probably just build a basic frame offset from the wall for now, and pack behind with Rockwool, faced with plywood like yours.

[JohnMo]

Why not make something self supporting and not touch the walls at all, something like this, but make it nice and solid 

 

[saveasteading]

Acoustic rail / resilient bar is useful in stopping vibrations carrying through

 

I once had a roll of a bitumen sort of sheet with lead trapped within. It was made for medical aprons to stop x-rays.

Very heavy but also flexible, and I used it on a party wall , hung loose behind the plasterboard, to great effect.

It isn't available and would be crazily expensive, but some other heavyish loose material could be used. thick polyethene etc.